EP0677754B1 - Bohrlochvorrichtung mit einer Beschleunigerneutronenquelle - Google Patents

Bohrlochvorrichtung mit einer Beschleunigerneutronenquelle Download PDF

Info

Publication number
EP0677754B1
EP0677754B1 EP95302295A EP95302295A EP0677754B1 EP 0677754 B1 EP0677754 B1 EP 0677754B1 EP 95302295 A EP95302295 A EP 95302295A EP 95302295 A EP95302295 A EP 95302295A EP 0677754 B1 EP0677754 B1 EP 0677754B1
Authority
EP
European Patent Office
Prior art keywords
neutrons
neutron
formation
source
detector
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP95302295A
Other languages
English (en)
French (fr)
Other versions
EP0677754A1 (de
Inventor
Kenneth E. Stephenson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Services Petroliers Schlumberger SA
Gemalto Terminals Ltd
Schlumberger Holdings Ltd
Schlumberger Technology BV
Schlumberger NV
Schlumberger Ltd USA
Original Assignee
Services Petroliers Schlumberger SA
Gemalto Terminals Ltd
Schlumberger Holdings Ltd
Schlumberger Technology BV
Schlumberger NV
Schlumberger Ltd USA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Services Petroliers Schlumberger SA, Gemalto Terminals Ltd, Schlumberger Holdings Ltd, Schlumberger Technology BV, Schlumberger NV, Schlumberger Ltd USA filed Critical Services Petroliers Schlumberger SA
Publication of EP0677754A1 publication Critical patent/EP0677754A1/de
Application granted granted Critical
Publication of EP0677754B1 publication Critical patent/EP0677754B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V5/00—Prospecting or detecting by the use of nuclear radiation, e.g. of natural or induced radioactivity
    • G01V5/04—Prospecting or detecting by the use of nuclear radiation, e.g. of natural or induced radioactivity specially adapted for well-logging
    • G01V5/08—Prospecting or detecting by the use of nuclear radiation, e.g. of natural or induced radioactivity specially adapted for well-logging using primary nuclear radiation sources or X-rays
    • G01V5/10—Prospecting or detecting by the use of nuclear radiation, e.g. of natural or induced radioactivity specially adapted for well-logging using primary nuclear radiation sources or X-rays using neutron sources
    • G01V5/107—Prospecting or detecting by the use of nuclear radiation, e.g. of natural or induced radioactivity specially adapted for well-logging using primary nuclear radiation sources or X-rays using neutron sources and detecting reflected or back-scattered neutrons

Definitions

  • the present invention relates to a method and apparatus for well logging to determine a characteristic of an underground formation through which the well passes.
  • the invention relates to a logging technique which uses an accelerator neutron source.
  • a neutron source in a logging tool for obtaining a characteristic of a formation surrounding a borehole is well known, particularly in the derivation of formation porosity.
  • Certain techniques involve the use of a chemical source such as 252 Cf AmBe or PuBe to provide neutrons to irradiate the formation such that scattered neutrons returning to the borehole can be detected and the formation characteristic (porosity) inferred.
  • a chemical source such as 252 Cf AmBe or PuBe to provide neutrons to irradiate the formation such that scattered neutrons returning to the borehole can be detected and the formation characteristic (porosity) inferred.
  • Such tools and methods are described in US 3,483,376 and US 3,566,117.
  • chemical neutron sources have several disadvantages due to the problems in handling and shipping sources containing radioactive materials due to concerns over radioactive safety and other such matters.
  • accelerator neutron sources are those base on the deuterium-tritium (D-T) reaction which produces 14MeV neutrons, the deuterium-deuterium (D-D) reaction which produces 2.5 MeV neutrons and the tritium-tritium (T-T) reaction which produces neutrons in the range 1-10 MeV with an average energy of about 5 MeV.
  • D-T deuterium-tritium
  • D-D deuterium-deuterium
  • T-T tritium-tritium
  • the '252 patent describes a neutron porosity logging tool in which an accelerator source is used to irradiate the underground formation and epithermal and thermal neutrons returning from the formation are detected. Scattering of neutrons in the formation at epithermal and thermal energies is due to interaction of the neutrons with hydrogen nuclei and so monitoring the neutrons at these energies is used to estimate the porosity of the formation since hydrogen is only associated with pore fluids rather than the rock matrix.
  • the neutron porosity measurement is essentially a measurement of hydrogen density in the formation.
  • an increase in matrix density for a formation can result in a decrease in count rate for a neutron porosity tool in much the same way that an increase in porosity would cause a decrease in count rate. Since it is not possible to determine which effect is causing the change merely by considering the neutron count, it is necessary to obtain an independent determination of the formation density.
  • the formation density is obtained from a tool which makes use of Compton scattering of ⁇ rays by electrons to make formation matrix density measurements.
  • the density tool requires a source of ⁇ rays, typically a 137 Cs isotopic source.
  • GB-A-828,917 describes a borehole tool for determining characteristics of underground formations.
  • a source of neutrons at two different energies, including energies of 1 MeV and above is used to irradiate the formation and detectors are used to detect radiation resulting from such irradiation. The radiation detected is analysed to obtain information about the matrix of the underground formation.
  • the tool described in the '252 patent uses 3 He filled proportional counters to detect neutrons.
  • Such counters are typically filled with 3 He at pressures in the 10-15 atmospheres range although it has been proposed to use pressures as high as 20 atmospheres in proportional neutron counters (see US 3,102,198) and even up to 40 atmospheres, and are sensitive mainly to epithermal and thermal neutrons.
  • 3 He proportional counters suffer from certain problems.
  • the signal in a 3 He counter is produced by a proton which is the result of the reaction between a He nucleus and a neutron.
  • signals can also be produced by the interaction of a 3 He nucleus with a ⁇ ray and this interferes with the signal produced by neutron interactions.
  • the normal approach to discriminating between neutron and ⁇ ray induced events is by peak height/signal strength analysis since the neutron induced events occur at different energies to ⁇ ray events.
  • This problem is compounded by increasing the He pressure inside the counter which, while increasing the sensitivity of the counter to neutron events, makes the counter comparatively more sensitive to ⁇ ray induced events and so the interfering effect is greater. This problem is particularly significant in a borehole environment where the naturally occurring ⁇ ray activity is high.
  • 4 He has been used in proportional counters for detecting neutrons having MeV energies. However, 4 He has a strong resonance at 1MeV which makes the neutron response highly energy dependent. Furthermore, 4 He has a cutoff in the response below 1 MeV which makes it insensitive to epithermal neutrons. For this reason, 4 He has not been considered as generally acceptable for proportional counters in neutron detectors.
  • a first aspect of the present invention provides a method of determining a characteristic of an underground formation through which a' borehole passes comprising using a tool comprising a high-energy neutron source and neutron detectors, the method comprising irradiating the underground formation with neutrons from the neutron source, detecting neutrons passing to the detectors from the formation so as to produce a signal and using the signal to determine the characteristic of the underground formation, characterised in that the detectors comprise a high pressure 4 He proportional counter which detects neutrons having energies of about' 1 MeV which have passed from the source to the counter via the formation, and produces a signal from which the characteristic of the formation is determined.
  • a second aspect of the invention provides apparatus for determining a characteristic of an underground formation through which a borehole passes comprising a high-energy neutron source for irradiating the underground formation with neutrons when the apparatus is positioned in the borehole, and a neutron detectors arranged to detect neutrons arriving from the formation so as to produce a signal related to the characteristic of the underground formation, characterised in that the detectors comprise a high pressure 4 He proportional counter including 4 He at a pressures of about 40 atm for detecting neutrons originating from the source arriving from the formation.
  • the invention comprises a technique for determining the nature of the underground formation matrix, comprising irradiating the formation with 14 MeV neutrons from a D-T accelerator and detecting neutrons at about 1MeV which have passed through the formation and have been slowed down by scattering with nuclei in the formation so as to determine the slowing down length for the 14-1 MeV transport which can be used to give useful information about the composition of the formation and the presence of gas.
  • the invention also comprises monitoring the flow of neutrons directly from the accelerator source, typically a D-T accelerator producing 14 MeV neutrons, and which have not passed through the underground formation.
  • the accelerator source typically a D-T accelerator producing 14 MeV neutrons
  • the detector comprises a high pressure 4 He proportional counter and that the 4 He pressure in the counter be as high as possible, typically in the region of 40 atmospheres. Where the detector is used to detect neutrons which have been scattered by the formation, the high Z shielding is absent.
  • FIG. 1 shows a schematic view of a prior art tool as described in US 4,760,252.
  • the tool comprises a tool body or sonde 10 which can be lowered into a borehole and logged using a wireline cable in the conventional manner.
  • the sonde 10 includes a DT accelerator neutron source 12, a source monitor 14 for monitoring the neutron output of the source 12, a near epithermal neutron detector 16, a thermal/epithermal neutron detector array 17, a far epithermal neutron detector 18 and a thermal neutron detector 20.
  • the monitor 14 can typically comprise a scintillator and photo multiplier tube arrangement and the detectors 16, 17, 18 and 20 are 15 atm 3 He proportional counters having appropriate shielding in the form of Cd metal and B 4 C epoxy.
  • a tool according to the present invention will have generally the same configurations this prior art tool, but with the differences which will be described below.
  • FIG. 2 shows a schematic view of a tool according one embodiment of the present invention.
  • the tool comprises a sonde 30 including a D-T accelerator neutron source 32 which produces 14 MeV neutrons when activated, a near neutron detector 34 comprising a 40 atm 4 He proportional counter shielded with a layer of tungsten 36 (or other high -Z material such as tantalum, uranium, lead and bismuth).
  • tungsten 36 or other high -Z material such as tantalum, uranium, lead and bismuth.
  • the path length of 14 MeV neutrons through the shielding material should be at least 1 mean-free-path for an (n, 2n) reaction, which for tungsten is 7.9 cm.
  • a far neutron detector 38 comprises a further 40 atm 4 He proportional counter.
  • the counters 34 and 38 are located 5"-9" and 20"-75" from the source 32, respectively.
  • the near detector can comprise some form of source monitor other than a 4 He counter such as a scintillator in which case the high-Z shielding might not be required.
  • Another alternative comprises 3 He proportional counters as well as 4 He proportional counters as the near and/or far detectors in order to measure epithermal and thermal neutrons as well as those of MeV energies.
  • An intermediate detector array 37 can also be present.
  • the 40 atm 4 He proportional counters 34, 38 are of similar size and shape to the conventional 15 atm 3 He counters and the output signal is in a generally similar form. Certain aspects of the counter construction may need to be different to withstand the higher pressure inside the counter. 40 atm 4 He proportional counter of the type described can be obtained from GE Reuter Stokes Inc. of Twinsburg, Ohio, USA.
  • the 4 He scattering cross section for neutrons in the 0-14 MeV energy range is shown in Figure 3.
  • the scattering spectrum does not have any strong peaks which can be used for gain stabilization so an internal ⁇ -source, such as 234 U may be added.
  • gain stabilization requires a pulsed accelerator so that the ⁇ -source counts can be accumulated during source-off periods.
  • the 1 MeV resonance might normally be considered detrimental to the performance of a neutron detector.
  • this feature can be put to use when using a 14 MeV neutron source both when attempting to obtain the characteristics of the formation matrix and when attempting to discriminate against epithermal neutrons.
  • the neutrons interact with tungsten nuclei in the shielding to produce two product neutrons (another possible reaction produces three product neutrons).
  • This reaction has a negative Q value equal to the binding energy of a neutron, approximately -6.5 MeV. The remaining 7.5 MeV is shared among the product neutrons.
  • the cross section for this reaction is shown in Figure 4 and given the high nuclear density in metallic tungsten, the interaction probability is large (mean free path for an (n,2n) reaction is 7.9 cm).
  • the effect of the shielding not only increases the number of neutrons entering the counter due to the (n, 2n) reaction, but also brings these neutrons into the highly sensitive range of the counter around 1 MeV.
  • the high threshold for the reaction discriminates against neutrons which have scattered many times, such as in the formation, with a corresponding loss in energy and the low energy cut off in the detector response described above means that the detector is less sensitive to neutrons which a have not traveled directly from the source.
  • a conventional 3 He source monitor about 50% of the detected neutrons have been scattered by the formation rather than emanating directly from the source whereas in the tungsten shielded high pressure 4 He detector this figure is reduced to about 20%.
  • the other effect of shielding the source monitor in this manner is to reduce the flow of 14 MeV neutrons along the tool to the far detector.
  • hydrogenous shielding material may be placed between the source monitor and the far detector. This means that substantially all 1 MeV neutrons detected at the far detector result from interaction with the formation. If the near detector/source monitor is not a 4 He counter with tungsten shielding, it may be necessary to place some high-Z and hydrogenous shielding in the sonde to reduce the neutron flux through the tool directly from the source to the far detector.
  • Figure 5 shows the amplitude of the high pressure 4 He detector response against time with both signals due to neutrons and ⁇ rays shown.
  • the neutron induced signal is predominantly fast ( ⁇ 150 ns), low energy 4 He recoil with some slower, high energy 4 He recoil.
  • the ⁇ ray signal is predominantly slow (up to 10 ns).
  • One way to discriminate between neutron and ⁇ ray signals is to monitor only the first section of the signal, the fast signal, since this is mainly due to neutrons with little contribution from ⁇ rays.
  • the portion of the signal to be measured can be determined from the variation in neutron signal with time and the time required up to the peak in the neutron signal is chosen. This is typically in the 100-150 ns range.
  • Figure 6a comprises a cross plot of fast signals and slow signals when the source is not active, i.e. the signals are due to formation activity and thermal capture ⁇ rays only. As will be seen, most of the signal is present in a localized region ⁇ .
  • Figure 6b shows the corresponding cross plot with the neutron source active.
  • the 14-1 MeV transport in the formation is due to non-elastic reactions (mostly inelastic scattering, (n,p) and (n, ⁇ ) reactions) of the neutrons with nuclei such as C, O, Si, etc. contained in the rock matrix rather than hydrogen nuclei in the pore fluid which affect the transport below 1 MeV to epithermal and thermal energies.
  • nuclei such as C, O, Si, etc. contained in the rock matrix rather than hydrogen nuclei in the pore fluid which affect the transport below 1 MeV to epithermal and thermal energies.
  • neutrons with about 1 MeV energy have had to traverse the entire 14 - 1 MeV region where the non-elastic cross section is large and so show the greatest sensitivity to matrix effects (with some dependence also on hydrogen). Consequently, by determining the 14-1 MeV slowing down length L h , which is possible with the present invention, it is possible to obtain formation matrix information which is not available in the prior art techniques.
  • Simple diffusion theory predicts a radial falloff of flux ⁇ h with distance r from the source according to: where S is the source strength and ⁇ rs is the macroscopic cross section for removal from the energy range 1 - 14 MeV. Given two measurements of the 1 MeV flux at different source/detector spacings r 1 and r 2 , one can measure L h directly:
  • the epithermal flux ⁇ epi follows a similar law in one group diffusion theory: where L s is the length for slowing down from 14 MeV to 0.5 eV (the cadmium cutoff). Although L has some dependence on the matrix, flux dependence on these variations vanishes at a source/detector spacing of 2 L s .
  • the source factor S can be eliminated by taking a ratio with a 1 MeV flux measurement at a short source/detector spacing.
  • an epithermal detector ( 3 He) at 2 L s and two 1 MeV detectors ( 4 He) at different spacings one can measure both porosity (hydrogen index) and L h .
  • a crossplot of these two can determine matrix and identify gas as shown in Figure 8.
  • a crossplot of the detector flux ratios can be produced as shown in Figure 9.
  • the three curves shown correspond to the three major rock matrices: dolomite (2.87 g/cc), limestone (2.71 g/cc) and sandstone (2.65 g/cc).
  • dolomite (2.87 g/cc)
  • limestone (2.71 g/cc)
  • sandstone (2.65 g/cc).
  • the near/far and near/array ratios provide almost independent measures of matrix type and porosity, respectively.

Claims (30)

  1. Verfahren zum Bestimmen einer Eigenschaft einer unterirdischen Formation, durch die sich ein Bohrloch erstreckt, unter Verwendung eines Werkzeugs (30) mit einer Quelle (32) für energiereiche Neutronen und mit Neutronendetektoren, wobei das Verfahren umfaßt: Bestrahlen der unterirdischen Formation mit Neutronen aus der Neutronenquelle (32), Erfassen der Neutronen, die aus der Formation zu den Detektoren gelangen, um ein Signal zu erzeugen, und Verwenden des Signals zum Bestimmen der Eigenschaft der unterirdischen Formation, dadurch gekennzeichnet, daß die Detektoren einen Hochdruck-4HE-Proportionalzähler (38) umfassen, der Neutronen mit Energien von etwa 1 MeV erfaßt, die von der Quelle (32) durch die Formation zu dem Zähler (38) gelangt sind, und ein Signal erzeugt, mit dem die Eigenschaft der unterirdischen Formation bestimmt wird.
  2. Verfahren nach Anspruch 1, umfassend Bestrahlen der Formation mit Neutronen mit Energien von etwa 14 MeV.
  3. Verfahren nach Anspruch 1 oder 2, umfassend Verwenden des Signals zum Bestimmen der Beschaffenheit der Formationsmatrix.
  4. Verfahren nach Anspruch 1, 2 oder 3, ferner umfassend Erfassen von Neutronen, die aus der Neutronenquelle (32) stammen und ohne Durchgang durch die unterirdische Formation direkt zu einem Neutronendetektor (34) gelangen.
  5. Verfahren nach Anspruch 4, umfassend Erfassen von Neutronen mit Energien von etwa 14 MeV mit dem Neutronendetektor (34).
  6. Verfahren nach einem der vorhergehenden Ansprüche, umfassend Erfassen auch von Neutronen mit epithermen Energien an einem Detektor (37), um ein Epithermneutronensignal zu erzeugen, und Verwenden des Epithermneutronensignals zum Bestimmen der Eigenschaft der Formation.
  7. Verfahren nach Anspruch 6, umfassend Verwenden des Epithermneutronensignals, um einen Hinweis auf eine Formationsporosität zu erhalten, die verwendet wird, um die Eigenschaft der Formation zu bestimmen.
  8. Verfahren nach einem der vorhergehenden Ansprüche, umfassend Erzeugen von Neutronen an der Neutronenquelle unter Verwendung einer D-T-Beschleunigerquelle (32).
  9. Verfahren nach einem der vorhergehenden Ansprüche, umfassend Erfassen von Neutronen unter zwei verschiedenen Abständen von der Neutronenquelle (32).
  10. Verfahren nach Anspruch 9, bei dem das Werkzeug erste und zweite Hochdruck-4He-Proportionalzähler (34, 38) umfaßt, wobei der erste (34) näher zur Neutronenquelle (32) ist als der zweite (38); wobei das Verfahren umfaßt: Erfassen von aus der Neutronenquelle (32) stammenden Neutronen an dem ersten und zweiten Hochdruck-4He-Proportionalzähler (34, 38) zum Erzeugen eines ersten bzw. zweiten Signals und Verwenden des ersten und zweiten Signals zum Ableiten eines Hinweises auf die Eigenschaft der unterirdischen Formation.
  11. Verfahren nach Anspruch 10, umfassend Erfassen von aus der Neutronenquelle (32) stammenden Neutronen, die ohne die unterirdische Formation zu durchqueren direkt zu dem ersten Hochdruck-4He-Proportionalzähler (34) gelangt sind, und Erfassen von aus der Neutronenquelle (32) stammenden Neutronen, die durch die unterirdische Formation zum zweiten Hochdruck-4He-Proportionalzähler (38) gelangt sind.
  12. Verfahren nach Anspruch 10, umfassend Erfassen von aus der Neutronenquelle (32) stammenden Neutronen, die durch die unterirdische Formation zu sowohl dem ersten als auch dem zweiten Hochdruck-4He-Proportionalzähler (34, 38) gelangt sind.
  13. Verfahren nach Anspruch 10, 11 oder 12, umfassend Bestimmen des Verhältnisses zwischen dem ersten und dem zweiten Signal zum Ableiten der Eigenschaft der unterirdischen Formation.
  14. Verfahren nach einem der vorhergehenden Ansprüche, bei dem der Neutronendetektor (34) einen Hochdruck-4He-Proportionalzähler umfaßt, der mit einem Material (36) abgeschirmt ist, das mit den aus der Neutronenquelle (32) stammenden Neutronen unter Erzeugung einer im Vergleich mit der Anzahl von aus der Neutronenquelle (32) stammenden Neutronen, die mit dem Abschirmmaterial (36) wechselwirken, erhöhten Anzahl von Neutronen, die in die Hochdruck-4He-Proportionalzähler (34) eintreten, wechselwirkt, wobei das Verfahren ein Erfassen der erhöhten Anzahl von Neutronen zum Erzeugen des Signals umfaßt.
  15. Verfahren nach Anspruch 14, bei dem das Abschirmmaterial (36) Wolfram ist.
  16. Vorrichtung zum Bestimmen einer Eigenschaft einer unterirdischen Formation, durch die sich ein Bohrloch erstreckt, mit einer Quelle (32) für energiereiche Neutronen zum Bestrahlen der unterirdischen Formation mit Neutronen, wenn die Vorrichtung im Bohrloch angeordnet wird, und Neutronendetektoren, die so angeordnet sind, daß sie Neutronen erfassen, die aus der Formation ankommen, um ein Signal zu erzeugen, das mit der Eigenschaft der unterirdischen Formation in Bezug steht, dadurch gekennzeichnet, daß die Detektoren einen Hochdruck-4He-Proportionalzähler (38) mit 4He bei einem Druck von etwa 40 atm zum Erfassen von Neutronen aufweisen, die aus der Quelle (32) stammend aus der Formation ankommen.
  17. Vorrichtung nach Anspruch 16, bei der die Quelle (32) für energiereiche Neutronen eine D-T-Beschleunigerquelle umfaßt.
  18. Vorrichtung nach Anspruch 16 oder 17, bei der die Neutronenquelle (32) Neutronen erzeugt, die eine Energie von etwa 14 MeV aufweisen.
  19. Vorrichtung nach einem der Ansprüche 16 bis 18, bei der der Detektor (38) auf Neutronen mit Energien von etwa 1 MeV reagiert.
  20. Vorrichtung nach einem der Ansprüche 16 bis 19, ferner umfassend einen Detektor (37) für epitherme Neutronen.
  21. Vorrichtung nach Anspruch 20, bei der der Detektor (37) für epitherme Neutronen 2LS von der Neutronenquelle (32) beabstandet ist, wobei LS die Bremsentfernung von 14 MeV auf 0,5 MeV darstellt.
  22. Vorrichtung nach einem der Ansprüche 16 bis 21, ferner umfassend einen weiteren Neutronendetektor (34), der auf aus der Neutronenquelle (32) stammende Neutronen reagiert, die ohne Durchgang durch die unterirdische Formation direkt zum weiteren Neutronendetektor (34) gelangen.
  23. Vorrichtung nach Anspruch 22, bei der der weitere Neutronendetektor (34) einen Hochdruck-4He-Proportionalzähler umfaßt, der mit einem Material (36) abgeschirmt ist, das mit aus der Neutronenquelle (32) stammenden Neutronen derart wechselwirkt, daß eine im Vergleich mit der Anzahl der von der Quelle (32) ankommenden Neutronen erhöhte Anzahl von Neutronen, die in den Zähler (34) eintreten, erzeugt wird.
  24. Vorrichtung nach Anspruch 23, bei der das Abschirmmaterial (36) Wolfram aufweist.
  25. Vorrichtung nach Anspruch 22, 23 oder 24, bei der der weitere Neutronendetektor (34) auf Neutronen mit einer Energie von etwa 14 MeV reagiert.
  26. Vorrichtung nach einem der Ansprüche 16 bis 25, mit einem ersten und einem zweiten Hochdruck-4He-Proportionalzähler (34, 38), wobei der erste (34) näher an der Neutronenquelle (32) als der zweite (38) ist, wobei der erste und der zweite Hochdruck-4He-Proportionalzähler (34, 38) ein erstes bzw. ein zweites Signal erzeugt, die verwendet werden, um das mit der Eigenschaft der unterirdischen Formation in Beziehung stehende Signal abzuleiten.
  27. Vorrichtung nach Anspruch 26, bei der der erste Detektor (34) auf Neutronen reagiert, die ohne Durchgang durch die Formation direkt aus der Neutronenquelle (32) ankommen, und der zweite Detektor (38) auf Neutronen reagiert, die aus der Neutronenquelle (32) stammen und über die unterirdische Formation ankommen.
  28. Vorrichtung nach Anspruch 26 oder 27, umfassend Mittel zum Bestimmen des Verhältnisses zwischen dem ersten und dem zweiten Signal, um die Eigenschaft der unterirdischen Formation abzuleiten.
  29. Vorrichtung nach einem der Ansprüche 16 bis 28, umfassend ein Datenerfassungs-Drahtleitungs-Werkzeug.
  30. Vorrichtung nach einem der Ansprüche 16 bis 28, umfassend ein Werkzeug zur Datenerfassung während des Bohrens.
EP95302295A 1994-04-12 1995-04-06 Bohrlochvorrichtung mit einer Beschleunigerneutronenquelle Expired - Lifetime EP0677754B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US226737 1988-08-01
US22673794A 1994-04-12 1994-04-12

Publications (2)

Publication Number Publication Date
EP0677754A1 EP0677754A1 (de) 1995-10-18
EP0677754B1 true EP0677754B1 (de) 2004-12-15

Family

ID=22850192

Family Applications (1)

Application Number Title Priority Date Filing Date
EP95302295A Expired - Lifetime EP0677754B1 (de) 1994-04-12 1995-04-06 Bohrlochvorrichtung mit einer Beschleunigerneutronenquelle

Country Status (5)

Country Link
US (1) US5532482A (de)
EP (1) EP0677754B1 (de)
CA (1) CA2146618C (de)
DE (1) DE69533850D1 (de)
NO (1) NO319373B1 (de)

Families Citing this family (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB9624899D0 (en) * 1996-11-29 1997-01-15 Schlumberger Ltd Method and apparatus for measuring flow in a horizontal borehole
US5973328A (en) * 1997-10-29 1999-10-26 Lockheed Martin Energy Research Corporation Neutron detector using sol-gel absorber
US7582880B2 (en) * 2002-03-20 2009-09-01 Neutron Sciences, Inc. Neutron detector using lithiated glass-scintillating particle composite
US20050135535A1 (en) * 2003-06-05 2005-06-23 Neutron Sciences, Inc. Neutron detector using neutron absorbing scintillating particulates in plastic
US7439519B2 (en) * 2006-09-18 2008-10-21 Nova Scientific, Inc. Neutron detection based on coincidence signal
US8173967B2 (en) * 2007-03-07 2012-05-08 Nova Scientific, Inc. Radiation detectors and related methods
US7791017B2 (en) * 2007-07-23 2010-09-07 Schlumberger Technology Corporation Method to simultaneously determine pore hydrocarbon density and water saturation from pulsed neutron measurements
US9897719B2 (en) 2009-05-22 2018-02-20 Schlumberger Technology Corporation Optimization of neutron-gamma tools for inelastic-gamma ray logging
US9372277B2 (en) * 2010-04-21 2016-06-21 Schlumberger Technology Corporation Neutron porosity downhole tool with improved precision and reduced lithology effects
RU2457469C1 (ru) * 2011-06-23 2012-07-27 Общество с ограниченной ответственностью "Нейтронные технологии" Мобильное устройство для идентификации скрытых веществ (варианты)
US9632188B2 (en) * 2011-08-02 2017-04-25 Raytheon Company Noble gas detector for fissile content determination
RU2476864C1 (ru) * 2011-12-06 2013-02-27 Общество с ограниченной ответственностью "Нейтронные технологии" Переносной обнаружитель опасных скрытых веществ
RU2503955C1 (ru) * 2012-07-27 2014-01-10 Общество с ограниченной ответственностью "Детекторы взрывчатки и наркотиков" Устройство для обнаружения и идентификации скрытых опасных веществ под водой
RU2503954C1 (ru) * 2012-08-27 2014-01-10 Общество с ограниченной ответственностью "Детекторы взрывчатки и наркотиков" Устройство для обнаружения и индентификации скрытых опасных веществ под водой (варианты)
RU2502986C1 (ru) * 2012-09-07 2013-12-27 Федеральное государственное унитарное предприятие "Всероссийский научно-исследовательский институт автоматики им. Н.Л. Духова" Способ нейтронной радиографии
RU2505801C1 (ru) * 2012-09-07 2014-01-27 Федеральное государственное унитарное предприятие "Всероссийский научно-исследовательский институт автоматики им. Н.Л. Духова" Устройство нейтронной радиографии
RU2524754C1 (ru) * 2013-01-22 2014-08-10 Вячеслав Михайлович Быстрицкий Мобильный обнаружитель опасных скрытых веществ (варианты)
RU2549680C2 (ru) * 2013-01-22 2015-04-27 Вячеслав Михайлович Быстрицкий Досмотровый комплекс обнаружения опасных скрытых веществ (варианты)
US10444304B2 (en) 2014-03-26 2019-10-15 General Electric Company Particle event recordation

Family Cites Families (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB828917A (en) * 1956-04-19 1960-02-24 Schlumberger Well Surv Corp Improvements in or relating to well logging apparatus
US3102198A (en) * 1961-11-16 1963-08-27 Socony Mobil Oil Co Inc Sensitive low voltage proportional counter for neutron detection containing he3 at superatmospheric pressure
US3240971A (en) * 1962-05-29 1966-03-15 Texas Nuclear Corp Helium-3 thermal neutron proportional counter
US3483376A (en) * 1966-08-03 1969-12-09 Schlumberger Technology Corp Two neutron detector earth formation porosity logging technique
US3775216A (en) * 1967-03-31 1973-11-27 Schlumberger Technology Corp Neutron generating systems
US3566117A (en) * 1968-01-05 1971-02-23 Schlumberger Technology Corp Measuring technique
US4005290A (en) * 1975-06-25 1977-01-25 Mobil Oil Corporation Neutron-neutron logging
US4097737A (en) * 1976-11-01 1978-06-27 Mobil Oil Corporation Epithermal die-away porosity logging
US4268749A (en) * 1978-10-16 1981-05-19 Mobil Oil Corporation Method for directly monitoring the output of a neutron source in a borehole logging system
US4476391A (en) * 1982-03-08 1984-10-09 Mobil Oil Corporation Method for improving accuracy in a neutron detector
US4556793A (en) * 1983-04-07 1985-12-03 Mobil Oil Corporation Epithermal neutron lifetime logging
US4760252A (en) * 1983-06-28 1988-07-26 Schlumberger Technology Corporation Well logging tool with an accelerator neutron source
US4638161A (en) * 1983-10-24 1987-01-20 Halliburton Company Epithermal neutron porosity measurement
US4641028A (en) * 1984-02-09 1987-02-03 Taylor James A Neutron logging tool
US4581532A (en) * 1984-07-06 1986-04-08 Mobil Oil Corporation Directional epithermal neutron detector
US4604522A (en) * 1984-11-05 1986-08-05 Halliburton Company Method and apparatus for logging a borehole employing dual radiation detectors
US4631405A (en) * 1984-12-05 1986-12-23 Halliburton Company Method and apparatus for dual-spaced fast/epithermal neutron porosity measurements
EP0436990B1 (de) * 1986-06-05 1995-04-12 Schlumberger Limited Detektor zur Messung der Neutronenquelle mit einer Beschleuniger-Neutronenquelle
US4910397A (en) * 1989-01-10 1990-03-20 Mobil Oil Corporation Pulsed neutron porosity logging
US5160844A (en) * 1990-10-24 1992-11-03 Schlumberger Technology Corporation Gain stabilized neutron detector

Also Published As

Publication number Publication date
NO319373B1 (no) 2005-07-25
EP0677754A1 (de) 1995-10-18
CA2146618A1 (en) 1995-10-13
NO951420L (no) 1995-10-13
NO951420D0 (no) 1995-04-11
DE69533850D1 (de) 2005-01-20
CA2146618C (en) 2004-06-08
US5532482A (en) 1996-07-02

Similar Documents

Publication Publication Date Title
EP0677754B1 (de) Bohrlochvorrichtung mit einer Beschleunigerneutronenquelle
US4760252A (en) Well logging tool with an accelerator neutron source
JP4195522B2 (ja) 土類層の濃度判別方法
CA2895251C (en) Geometrically optimized fast neutron detector
AU733374C (en) Formation density measurement utilizing pulsed neutrons
CA2356742C (en) Neutron burst timing method and system for multiple measurement pulsed neutron formation evaluation
US7642507B2 (en) Apparatus and methods for interlaced density and neutron measurements
EP0790508B1 (de) Verfahren und Vorrichtung zur Feststellung der Dichte von Erdformationen
US5539225A (en) Accelerator-based methods and apparatus for measurement-while-drilling
US7081616B2 (en) Downhole gamma-ray detection
US20020170348A1 (en) Well logging apparatus and method for measuring formation properties
US20020130267A1 (en) Geometrically optimized fast neutron detector
US20020130268A1 (en) Geometrically optimized fast neutron detector
EP0269620B1 (de) Bohrlochvorrichtung mit einer beschleunigerneutronenquelle
US5521378A (en) Method and apparatus for gamma ray logging of underground formations
US3925659A (en) Inelastic gamma ray logging system
US5789752A (en) Thermal neutron porosity measurement apparatus and method using an accelerator type high-energy neutron source
US4556793A (en) Epithermal neutron lifetime logging
Wilson Bulk density logging with high-energy gammas produced by fast neutron reactions with formation oxygen atoms
CN1015674B (zh) 带加速器中子源的测井仪
Antkiw et al. A well logging tool with an accelerator neutron source
Czirr et al. Flux normalization for dT sources
MXPA98001701A (en) Method to determine the density of the terrest formations

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE DK FR GB IT NL

17P Request for examination filed

Effective date: 19960326

17Q First examination report despatched

Effective date: 19970822

APAB Appeal dossier modified

Free format text: ORIGINAL CODE: EPIDOS NOAPE

APAB Appeal dossier modified

Free format text: ORIGINAL CODE: EPIDOS NOAPE

APAD Appeal reference recorded

Free format text: ORIGINAL CODE: EPIDOS REFNE

APBT Appeal procedure closed

Free format text: ORIGINAL CODE: EPIDOSNNOA9E

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE DK FR GB IT NL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20041215

Ref country code: IT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED.

Effective date: 20041215

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20041215

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

REF Corresponds to:

Ref document number: 69533850

Country of ref document: DE

Date of ref document: 20050120

Kind code of ref document: P

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20050315

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20050316

NLV1 Nl: lapsed or annulled due to failure to fulfill the requirements of art. 29p and 29m of the patents act
APAH Appeal reference modified

Free format text: ORIGINAL CODE: EPIDOSCREFNO

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed

Effective date: 20050916

EN Fr: translation not filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20120404

Year of fee payment: 18

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20130406

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20130406